diff --git a/.github/workflows/main.yml b/.github/workflows/main.yml
new file mode 100644
index 00000000..a7642566
--- /dev/null
+++ b/.github/workflows/main.yml
@@ -0,0 +1,56 @@
+
+name: Test & lint
+
+on:
+  workflow_dispatch:
+  pull_request:
+  push:
+    branches:
+      - main
+      - develop
+
+jobs:
+  spec:
+    runs-on: ubuntu-latest
+    name: Ruby ${{ matrix.ruby }} w/ ${{ matrix.gemfile }}
+    strategy:
+      fail-fast: false
+      matrix:
+        ruby:
+          - "2.6"
+          - "2.7"
+          - "3.0"
+          - "3.1"
+          - "3.2"
+        gemfile:
+          - tzinfo_2_0
+          - active_support_6_1
+          - active_support_7_0
+          - active_support_7_1
+        exclude:
+          - ruby: "2.6"
+            gemfile: active_support_7_0
+          - ruby: "2.6"
+            gemfile: active_support_7_1
+    env:
+      BUNDLE_GEMFILE: gemfiles/${{ matrix.gemfile }}.gemfile
+      BUNDLE_PATH: "gemfiles/vendor/bundle"
+
+    steps:
+      - uses: actions/checkout@v4
+      - name: Set up Ruby
+        uses: ruby/setup-ruby@v1
+        with:
+          ruby-version: ${{ matrix.ruby }}
+          bundler-cache: true
+      - uses: actions/cache@v3
+        with:
+          # NOTE: Bundler expands the path relative to the gemfile, not the
+          # current directory.
+          path: ./gemfiles/vendor/bundle
+          key: bundled-gems-${{ runner.os }}-ruby-${{ matrix.ruby }}-${{ matrix.gemfile }}-${{ hashFiles( 'gemfiles/*.lock' ) }}
+          restore-keys: |
+            bundled-gems-${{ runner.os }}-ruby-${{ matrix.ruby }}-${{ matrix.gemfile }}-
+            bundled-gems-${{ runner.os }}-ruby-${{ matrix.ruby }}-
+      - name: Run tests
+        run: bundle exec rspec
diff --git a/.gitignore b/.gitignore
index d87d4be6..eba00d5d 100644
--- a/.gitignore
+++ b/.gitignore
@@ -15,3 +15,4 @@ spec/reports
 test/tmp
 test/version_tmp
 tmp
+gemfiles/*.lock
diff --git a/.rspec b/.rspec
deleted file mode 100644
index e69de29b..00000000
diff --git a/.ruby-gemset b/.ruby-gemset
deleted file mode 100644
index 77d8d524..00000000
--- a/.ruby-gemset
+++ /dev/null
@@ -1 +0,0 @@
-kdgm-ri_cal
diff --git a/.ruby-version b/.ruby-version
deleted file mode 100644
index 23a63f52..00000000
--- a/.ruby-version
+++ /dev/null
@@ -1 +0,0 @@
-2.2.8
diff --git a/.travis.yml b/.travis.yml
deleted file mode 100644
index 8c0d4d10..00000000
--- a/.travis.yml
+++ /dev/null
@@ -1,6 +0,0 @@
-language: ruby
-rvm:
-  - 1.9.3-p551
-  - 2.2.8
-# uncomment this line if your project needs to run something other than `rake`:
-# script: bundle exec rspec spec
diff --git a/Appraisals b/Appraisals
new file mode 100644
index 00000000..3a58eefe
--- /dev/null
+++ b/Appraisals
@@ -0,0 +1,15 @@
+appraise "tzinfo_2_0" do
+  gem "tzinfo", "~> 2"
+end
+
+appraise "active_support_6_1" do
+  gem "activesupport", "~> 6.1.0", require: "active_support"
+end
+
+appraise "active_support_7_0" do
+  gem "activesupport", "~> 7.0.0", require: "active_support"
+end
+
+appraise "active_support_7_1" do
+  gem "activesupport", "~> 7.1.0", require: "active_support"
+end
diff --git a/gemfiles/active_support_6_1.gemfile b/gemfiles/active_support_6_1.gemfile
new file mode 100644
index 00000000..5b9831a2
--- /dev/null
+++ b/gemfiles/active_support_6_1.gemfile
@@ -0,0 +1,7 @@
+# This file was generated by Appraisal
+
+source "https://rubygems.org"
+
+gem "activesupport", "~> 6.1.0", require: "active_support"
+
+gemspec path: "../"
diff --git a/gemfiles/active_support_7_0.gemfile b/gemfiles/active_support_7_0.gemfile
new file mode 100644
index 00000000..79954297
--- /dev/null
+++ b/gemfiles/active_support_7_0.gemfile
@@ -0,0 +1,7 @@
+# This file was generated by Appraisal
+
+source "https://rubygems.org"
+
+gem "activesupport", "~> 7.0.0", require: "active_support"
+
+gemspec path: "../"
diff --git a/gemfiles/active_support_7_1.gemfile b/gemfiles/active_support_7_1.gemfile
new file mode 100644
index 00000000..2e683e1b
--- /dev/null
+++ b/gemfiles/active_support_7_1.gemfile
@@ -0,0 +1,7 @@
+# This file was generated by Appraisal
+
+source "https://rubygems.org"
+
+gem "activesupport", "~> 7.1.0", require: "active_support"
+
+gemspec path: "../"
diff --git a/gemfiles/tzinfo_2_0.gemfile b/gemfiles/tzinfo_2_0.gemfile
new file mode 100644
index 00000000..81ebb3c7
--- /dev/null
+++ b/gemfiles/tzinfo_2_0.gemfile
@@ -0,0 +1,7 @@
+# This file was generated by Appraisal
+
+source "https://rubygems.org"
+
+gem "tzinfo", "~> 2"
+
+gemspec path: "../"
diff --git a/lib/ri_cal/component/t_z_info_timezone.rb b/lib/ri_cal/component/t_z_info_timezone.rb
index e0a6ae78..c010236a 100644
--- a/lib/ri_cal/component/t_z_info_timezone.rb
+++ b/lib/ri_cal/component/t_z_info_timezone.rb
@@ -22,20 +22,20 @@ def initialize(which, this_period, prev_period)
       @abbreviation = this_period.abbreviation
       @rdates = []
     end
-    
+
     def daylight?
       @which == "DAYLIGHT"
     end
-    
+
     def period_local_end(period)
-      (period.local_end || DateTime.parse("99990101T000000")).strftime("%Y%m%dT%H%M%S")
+      (period.local_ends_at&.to_datetime || DateTime.parse("99990101T000000")).strftime("%Y%m%dT%H%M%S")
     end
-    
+
     # This assumes a 1 hour shift which is why we use the previous period local end when
     # possible
     def period_local_start(period)
       shift = daylight? ? Rational(-1, 24) : Rational(1, 24)
-      ((period.local_start || DateTime.parse("16010101T000000")) + shift).strftime("%Y%m%dT%H%M%S")
+      ((period.local_starts_at&.to_datetime || DateTime.parse("16010101T000000")) + shift).strftime("%Y%m%dT%H%M%S")
     end
 
     def add_period(this_period)
@@ -69,7 +69,7 @@ class Periods #:nodoc: all
     def initialize
       @dst_period = @std_period = @previous_period = nil
     end
-    
+
     def empty?
       @periods.nil? || @periods.empty?
     end
@@ -86,7 +86,7 @@ def log_period(period)
       @periods ||= []
       @periods << period unless @periods.include?(period)
     end
-    
+
     def add_period(this_period, force=false)
       if @previous_period || force
         if this_period.dst?
@@ -110,7 +110,7 @@ def export_to(export_stream)
   def initialize(tzinfo_timezone) #:nodoc:
     @tzinfo_timezone = tzinfo_timezone
   end
-  
+
   # convert time from this time zone to utc time
   def local_to_utc(time, dst_ambiguity=nil)
     @tzinfo_timezone.local_to_utc(time.to_ri_cal_ruby_value, dst_ambiguity)
@@ -143,11 +143,11 @@ def export_utc_to(export_stream, utc_start, utc_end) #:nodoc:
     periods = Periods.new
     period = initial_period = tzinfo_timezone.period_for_utc(utc_start)
      #start with the period before the one containing utc_start
-    prev_period = period.utc_start && tzinfo_timezone.period_for_utc(period.utc_start - 1)
+    prev_period = period.starts_at && tzinfo_timezone.period_for_utc(period.starts_at.to_datetime - 1)
     period = prev_period if prev_period
-    while period && period.utc_start && period.utc_start < utc_end
+    while period && period.starts_at && period.starts_at.to_datetime < utc_end
       periods.add_period(period)
-      period = period.utc_end && tzinfo_timezone.period_for_utc(period.utc_end + 1)
+      period = period.ends_at && tzinfo_timezone.period_for_utc(period.ends_at.to_datetime + 1)
     end
     periods.add_period(initial_period, :force) if periods.empty?
     periods.export_to(export_stream)
diff --git a/ri_cal.gemspec b/ri_cal.gemspec
index f2bc4639..74d52e1c 100644
--- a/ri_cal.gemspec
+++ b/ri_cal.gemspec
@@ -1,5 +1,5 @@
 # -*- encoding: utf-8 -*-
-#- 2009 Rick DeNatale, All rights reserved. Refer to the file README.txt for the license
+# - 2009 Rick DeNatale, All rights reserved. Refer to the file README.txt for the license
 require File.join File.dirname(__FILE__), 'lib', 'ri_cal', 'version'
 Gem::Specification.new do |gem|
   gem.authors       = ["Jon Phenow, Rick DeNatale"]
@@ -21,11 +21,10 @@ A Google group for discussion of this library has been set up http://groups.goog
   gem.name          = "ri_cal"
   gem.require_paths = ["lib"]
   gem.version       = RiCal::VERSION
-  gem.required_ruby_version = '>= 1.9.3'
+  gem.required_ruby_version = '>= 2.6.7'
 
-  gem.add_dependency 'tzinfo'
+  gem.add_runtime_dependency 'tzinfo', "~> 2.0", "< 3.0"
 
-  gem.add_development_dependency 'activesupport', "~> 3.0.15"
   gem.add_development_dependency 'rake'
   gem.add_development_dependency 'rspec'
   gem.add_development_dependency 'rspec-its'
@@ -34,14 +33,5 @@ A Google group for discussion of this library has been set up http://groups.goog
   gem.add_development_dependency 'autotest-standalone'
   gem.add_development_dependency 'autotest-fsevent'
   gem.add_development_dependency 'awesome_print'
-
-  if gem.respond_to? :specification_version then
-    current_version = Gem::Specification::CURRENT_SPECIFICATION_VERSION
-    gem.specification_version = 3
-
-    if Gem::Version.new(Gem::VERSION) >= Gem::Version.new('1.2.0')
-    else
-    end
-  else
-  end
+  gem.add_development_dependency 'appraisal'
 end
diff --git a/spec/ri_cal/calendar_occurrences_edge_cases_spec.rb b/spec/ri_cal/calendar_occurrences_edge_cases_spec.rb
index 4303a3a5..70325c69 100644
--- a/spec/ri_cal/calendar_occurrences_edge_cases_spec.rb
+++ b/spec/ri_cal/calendar_occurrences_edge_cases_spec.rb
@@ -9,14 +9,14 @@ def generate_calendar(fixtures)
       dtstart, rrule = recurring.split('#')
       event do |e|
         e.uid = uid
-        e.dtstart = Time.parse(dtstart)
+        e.dtstart = DateTime.parse(dtstart)
         e.rrule = rrule if rrule
       end
       overrides.each do |dtfrom, dtto|
         event do |e|
           e.uid = uid
-          e.dtstart = Time.parse(dtto)
-          e.recurrence_id = Time.parse(dtfrom)
+          e.dtstart = DateTime.parse(dtto)
+          e.recurrence_id = DateTime.parse(dtfrom)
         end
       end
     end
@@ -26,7 +26,7 @@ def generate_calendar(fixtures)
 describe RiCal::Component::Calendar do
   
   context "move first override before range" do
-    let(:range) { { starting: Time.parse("2016-06-26"), count: 4 } }
+    let(:range) { { starting: DateTime.parse("2016-06-26"), count: 4 } }
     subject {
       generate_calendar(
         "Jun 26, 2016 16:30:00#FREQ=DAILY" => {
@@ -48,7 +48,7 @@ def generate_calendar(fixtures)
   end
   
   context "move last event in range to a later date outside range/count" do
-    let(:range) { { starting: Time.parse("2016-06-27"), count: 4 } }
+    let(:range) { { starting: DateTime.parse("2016-06-27"), count: 4 } }
     subject {
       generate_calendar(
         "Jun 26, 2016 16:30:00#FREQ=DAILY" => {
@@ -71,7 +71,7 @@ def generate_calendar(fixtures)
   end
   
   context "move all but last event out of range" do
-    let(:range) { { starting: Time.parse("2016-06-26"), before: Time.parse("2016-07-03") } }
+    let(:range) { { starting: DateTime.parse("2016-06-26"), before: DateTime.parse("2016-07-03") } }
     subject {
       generate_calendar(
         "Jun 26, 2016 16:30:00#FREQ=DAILY" => {
@@ -95,7 +95,7 @@ def generate_calendar(fixtures)
   end
   
   context "move overrides into empty range" do
-    let(:range) { { starting: Time.parse("2016-06-26"), before: Time.parse("2016-07-03") } }
+    let(:range) { { starting: DateTime.parse("2016-06-26"), before: DateTime.parse("2016-07-03") } }
     subject {
       generate_calendar(
         "Jul 03, 2016 16:30:00#FREQ=DAILY" => {
@@ -126,7 +126,7 @@ def generate_calendar(fixtures)
   end
   
   context "should distinguish coincident events" do
-    let(:range) { { starting: Time.parse("2016-06-26"), count: 8 } }
+    let(:range) { { starting: DateTime.parse("2016-06-26"), count: 8 } }
     subject {
       generate_calendar(
         "Jun 26, 2016 10:00:00#FREQ=DAILY#1" => {
@@ -158,7 +158,7 @@ def generate_calendar(fixtures)
   end
   
   context "should return correct next occurrence" do
-    let(:range) { { starting: Time.parse("2016-06-26"), count: 1 } }
+    let(:range) { { starting: DateTime.parse("2016-06-26"), count: 1 } }
     subject {
       generate_calendar(
         "Jun 26, 2016 10:00:00#FREQ=DAILY" => {
diff --git a/spec/ri_cal/calendar_occurrences_spec.rb b/spec/ri_cal/calendar_occurrences_spec.rb
index b90578dc..0661e7f8 100644
--- a/spec/ri_cal/calendar_occurrences_spec.rb
+++ b/spec/ri_cal/calendar_occurrences_spec.rb
@@ -260,7 +260,7 @@
       }
 
       it("should return correct date/times with `starting` set") {
-        subject.occurrences(starting: Time.parse("2016-06-29T11:30:00+02:00"), count: 3).map(&:dtstart).map(&:to_s).should eql(%w(
+        subject.occurrences(starting: DateTime.parse("2016-06-29T11:30:00+02:00"), count: 3).map(&:dtstart).map(&:to_s).should eql(%w(
           2016-07-06T12:00:00+02:00
           2016-07-13T12:00:00+02:00
           2016-07-20T12:00:00+02:00
@@ -428,7 +428,7 @@
         ])
       }
       it {
-        subject.occurrences(starting: Time.parse("2016-06-16T20:00:01+02:00"), count: 6).map(&:summary).should eql([
+        subject.occurrences(starting: DateTime.parse("2016-06-16T20:00:01+02:00"), count: 6).map(&:summary).should eql([
             "Test 2", # instance summary
             "Test 3", # instance summary
             "Test Woensdag 18:00", # instance different day, time, summary
@@ -438,7 +438,7 @@
         ])
       }
       it {
-        subject.occurrences(starting: Time.parse("2016-06-16T20:00:01+02:00"), before: Time.parse("2016-07-21T20:00:00+02:00")).map(&:summary).should eql([
+        subject.occurrences(starting: DateTime.parse("2016-06-16T20:00:01+02:00"), before: DateTime.parse("2016-07-21T20:00:00+02:00")).map(&:summary).should eql([
             "Test 2", # instance summary
             "Test 3", # instance summary
             "Test Woensdag 18:00", # instance different day, time, summary
@@ -516,7 +516,7 @@
       }
       
       it {
-        subject.occurrences(starting: Time.parse('2016-07-24 10:00:00'), count: 4).map{ |o| [o.dtstart.to_s, o.summary].join(' ') }.should eql([
+        subject.occurrences(starting: DateTime.parse('2016-07-24 10:00:00+02:00'), count: 4).map{ |o| [o.dtstart.to_s, o.summary].join(' ') }.should eql([
           "2016-07-24T10:00:00+02:00  dhr. N. Weeda",
           "2016-07-24T16:30:00+02:00  ds. W. M. van Wijk",
           "2016-07-31T10:00:00+02:00  ds. M. Oppenhuizen",
@@ -1199,7 +1199,7 @@
     subject {
       RiCal.Calendar do |cal|
         cal.event do |event|
-          event.dtstart = Time.parse("2016-06-27T15:00:00+02:00")
+          event.dtstart = DateTime.parse("2016-06-27T15:00:00+02:00")
           event.rrule   = "FREQ=WEEKLY"
         end
       end
@@ -1272,7 +1272,7 @@
     its(:events) { should have(2).items }
     it {
       subject.occurrences(
-        starting: Time.parse("2016-09-15 10:59:45 +0200"), count: 3).map(&:dtstart).map(&:to_s).should eql(%w(
+        starting: DateTime.parse("2016-09-15 10:59:45 +0200"), count: 3).map(&:dtstart).map(&:to_s).should eql(%w(
           2016-09-15T11:10:00+02:00
           2016-09-22T10:00:00+02:00
           2016-09-29T10:00:00+02:00